Report: Lost of soil strength likely led to dam collapses

Midland dam
Posted at 11:14 PM, Sep 13, 2021
and last updated 2021-09-13 23:14:19-04

MIDLAND, Mich. (AP) — A sudden loss of soil strength under saturated conditions most likely caused dams to collapse last year and contributed to flooding that forced evacuations of about 10,000 people.

That's according to an interim report commissioned by federal regulators and released Monday.

A five-member independent forensic team said there's “strong evidence” the failure of the Edenville and Sanford dams during steady rain in May 2020 came from static liquefaction.

The report says that's the “most plausible principal mechanism for the failure.”

The 42-page interim report says the team has “essentially completed” investigation into the physical mechanism of the failure, but “evaluation of human factors is still in progress.”

A final report is pending.